- 您现在的位置：买卖IC网 > Sheet目录1233 > NCP1605LCDTVGEVB (ON Semiconductor)BOARD EVAL NCP1605/1396
NCP1027
This difference might not be seen as a problem, but some
design specifications impose stringent conditions on the
maximum output current capability, regardless the line
input. Hence the need for an OPP input …
Since we want to limit the power to 12.8 W at high line,
let us calculate the needed peak current:
10 k W and R OPPU made of a series string of 4 1.0 M W
resistors plus a 10-turn 1.0 M W potentiometer set at its
maximum value. An amp-meter is inserted in series with
pin 7 and a volt-meter monitors its voltage with respect to
ground. Once the power supply is powered, slowly rotate
the potentiometer and observe both voltage and current
From equation 6: Ipeak +
2Pout
FSWLp h
= 693 mA to
going up at pin 7. At a certain time, as voltage and current
increase, the controller will shut down the power supply.
deliver 12.8 W at high line.
Compared to our 735 mA, we need to decrease the
setpoint by 6% roughly when V in equals 350 Vdc.
The NCP1027 hosts a special circuitry looking at the
couple voltage/current present on pin 7. Figure 39 shows
how to arrange components around the controller to obtain
Over Power Protection.
Bulk
The current at this time is the one we are looking for.
Suppose these experiments lead to 80 m A with a pin 7
activation voltage of 2.45 V. Final resistor equations are:
VbulkH = 375 Vdc ; the maximum voltage at which OPP
must shut down the controller
V bulkL = 200 Vdc ; the minimum voltage below which
OPP is not activated
I OPP = 80 m A ; the current in pin 7
V f = 2.45 V ; the voltage of pin 7 at the above
condition
ROPPU
ROPPL +
VbulkH- VbulkL
IOPP(VbulkL- Vf)
Vf + 27 k W
(eq. 7)
ROPPH + ROPPL bulkL
Current
Setpoint
Over Power
Protection
OPP
V
Vf
- Vf
+ 2.2 M W
(eq. 8)
ROPPL
GND
Figure 39. A resistive network reduces the
power capability in high-line conditions.
First, you need to know the required injected current and
the voltage across pin 7 to start activating OPP.
Experiments consist in wiring Figure 39 circuit and
running the power supply in conditions where it must shut
down (e.g. highest input voltage and maximum output
current per specification). For this, R OPPL can be put to
V DD
IRR
Ramp
If the OPP feature is not needed for some designs, it is
possible to ground it via a copper wire to the adjacent
ground pin. This can help to develop a larger copper area
in an application where the thermal resistance is an
important parameter.
Ramp Compensation
When operating in Continuous Conduction Mode
(CCM), current-mode power supplies can exhibit
so-called sub-harmonic oscillations. To cure this problem,
the designer must inject ramp compensation. The ramp can
either be added to the current sense information or directly
subtracted from the feedback signal. Figure 40 details the
internal arrangement of the ramp compensation circuitry.
Gate Reset
Control
Vp
RR
Figure 40. The Internal Feedback Chain and the Ramp Compensation Network
http://onsemi.com
22
发布紧急采购，3分钟左右您将得到回复。
相关PDF资料
NCP1608BOOSTGEVB
BOARD EVAL NCP1608 100W BOOST
NCP1631PFCGEVB
BOARD DEMO NCP1631 INTERLEAV PFC
NCP1650EVB
BOARD EVAL NCP1650 PFC CTLR
NCP1652L48VGEVB
BOARD EVAL 100W 48V NCP1652 PFC
NCP1653EVB
BOARD EVAL FOR NCP1653
NCP2993FCT2GEVB
BOARD EVAL NCP2993 AUDIO PWR AMP
NCP345SNT1G
IC DETECTOR OVER VOLTAGE 5TSOP
NCP346SN2T1G
IC DETECTOR OVER VOLTAGE 5TSOP
相关代理商/技术参数
NCP1606ADR2G
功能描述:功率因数校正 IC PWR FCTR CONTROLLER RoHS:否 制造商:Fairchild Semiconductor 开关频率:300 KHz 最大功率耗散: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel
NCP1606APG
功能描述:功率因数校正 IC LO CST PWR FCTR CONT RoHS:否 制造商:Fairchild Semiconductor 开关频率:300 KHz 最大功率耗散: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel
NCP1606BDR2G
功能描述:功率因数校正 IC PWR FCTR CONTROLLER RoHS:否 制造商:Fairchild Semiconductor 开关频率:300 KHz 最大功率耗散: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel
NCP1606BOOSTGEVB
功能描述:电源管理IC开发工具 OSPI NCP1606 100 W BOOST
RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V
NCP1606BPG
功能描述:功率因数校正 IC LO CST PWR FCTR CONT RoHS:否 制造商:Fairchild Semiconductor 开关频率:300 KHz 最大功率耗散: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel
NCP1607BDR2G
功能描述:功率因数校正 IC CST EFCT PW FCTR CTR RoHS:否 制造商:Fairchild Semiconductor 开关频率:300 KHz 最大功率耗散: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel
NCP1607BOOSTGEVB
功能描述:BOARD EVAL NCP1607 100W BOOST RoHS:是 类别:编程器，开发系统 >> 评估演示板和套件 系列:* 标准包装:1 系列:PCI Express® (PCIe) 主要目的:接口，收发器，PCI Express 嵌入式:- 已用 IC / 零件:DS80PCI800 主要属性:- 次要属性:- 已供物品:板
NCP1608BDR2G
功能描述:功率因数校正 IC COST EFFECT PWR FACT CONT RoHS:否 制造商:Fairchild Semiconductor 开关频率:300 KHz 最大功率耗散: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel